ttt, just so you know I know this one is dead
$5.00 a gal??? I've _never_ seen it go that high...about the highest I've seen was what I just paid for gas today, $1.89 for regular.
Apparantly, about hydrogen, it's highly flammable and unstable, also hard to keep in a tank (ie, if it leaks, you're dead.) I've also been told that it takes more energy to isolate hydrogen (and pollute) than to refine and burn gasoline, so we're back where we started. Hydrogen is just not feasable right now, and it won't be for at least 25 more years.
I firmly believe that diesel is the replacement for gasoline. In the next 5-10 years, every company is gonna figure out how to make a cost-effective diesel that burns clean and runs quiet (The powerstroke is a work of art, if only they could fit it under the hood of a Crown Vic!). They've already been doing it for years in Europe.
I think GM and to a lesser extent, Ford, still remembers their wounds from the 80s disasters when they attempted to make a passenger car diesel engine (though I'll tell you, that Olds diesel is pretty reliable if you take care of it!!). Watch, it will happen. Electric, hydrogen, solar...that's damn stupid stuff, and nobody will buy them for a _long_ time. But I think a diesel could be successfully marketed.